Injection valve, particularly for direct injection of fuel into the combustion chamber of an internal combustion engine

ABSTRACT

An injection valve is described, in particular for direct injection of fuel into a combustion chamber of an internal combustion engine, with a valve body having a valve opening surrounded by a valve seat to form a spray opening, and with a valve needle which is pressed into its closed position, has a closing head and extends through the valve opening so that the closing head which works together with the valve seat is in contact with the valve seat on the spray side when the valve is closed. To ensure accurate fuel metering that is constant over a long period of time with such an injection valve, a plurality of fuel channels distributed around the periphery are arranged in the flow path upstream from the spray opening so that streams or strands of fuel coming out of the fuel channels are essentially maintained until downstream from the spray opening, and the individual cross sections of the fuel channels (29, 29&#39;, 29&#34;) together define a cross section of the flow path through the valve which determines the flow rate.

FIELD OF THE INVENTION

The present invention relates to an injection valve, in particular fordirect injection of fuel into a combustion.

BACKGROUND INFORMATION

International Patent Publication No. WO 93/23172 describes aconventional injection valve for direct injection of fuel into thecombustion chamber of an internal combustion engine includes a valvebody arranged in a housing and having a valve opening which issurrounded by a valve seat arranged on the spray side and through whichthere extends a valve needle carrying a closing head so that the closinghead is in contact with the valve seat from the outside when the valveis closed.

When the valve needle moves out of its closed position against the forceof a closing spring into the spraying direction in order to spray fuel,the closing head is lifted up from the valve seat, forming an annularspray opening between the closing head and the valve seat. The crosssection of the spray opening is the narrowest cross section of the flowpath, determining the flow rate, through the valve and is determined bythe opening stroke of the valve needle.

The opening stroke of the valve needle is determined by an actuatingdevice acting on the valve needle, or if there are alignment errors, bya spring sleeve attached to the valve needle coming to rest against avalve needle guide body. Due to manufacturing tolerances, it istherefore difficult to accurately set the desired cross section of thespray opening. Furthermore, in prolonged operation of the known aninjection valve, changes may occur in the cross section of the sprayopening, because the means for limiting the stroke, as well as the valveseat and the sealing surface connected thereto, are subject to wear.

U.S. Patent No. 5,307,997 describes another conventional injection valvewhich includes a valve seat body with a valve opening serving as a sprayopening and a valve needle guide body with as guide bore for the valveneedle. A sealing surface provided on the valve needle is connected to avalve seat surrounding the valve opening on the side facing away fromthe spray area. Upstream of the spray opening there is a frusto-conicalswirl chamber bordered by a recess in the valve seat body and aprojection on the valve needle guide body.

Fuel is supplied to the swirl chamber through bore holes in the valveneedle guide body which form fuel channels. Each individual bore holehas a bore section with a reduced diameter toward the outlet end. Thesebore sections together form the narrowest cross section in the flow paththrough the injection valve required for fuel metering. Because of theswirl chamber downstream from the fuel channels, fuel with thisconventional injection valve is sprayed in the form of a uniform,continuous frusto-conical layer of fuel.

SUMMARY OF THE INVENTION

An exemplary embodiment of an injection valve according to the presentinvention has the advantage over the related art that the fuel channelswhich determine the narrowest flow cross section are protected fromsoiling, while on the other hand a stranded layer of fuel can besprayed. The frusto-conical layer of fuel in particular thus has a fueldistribution that varies in the peripheral direction. It is thereforepossible through a suitable design and arrangement of the fuel channelsto optimize the fuel distribution in the fuel layer for the respectivecombustion chamber, so that a contiguous mist of fuel-air mix with acombustible fuel-to-air ratio can be produced.

Taking into account the built-in rotational position of the injectionvalve, the mutual arrangement of the spark plug and injection valve andthe orientation of the injection valve with respect to the axis of thecombustion chamber, it is thus possible achieve such results as noliquid fuel being deposited on the wall of the combustion chamber or onthe piston bottom, the spark plug not cooling off too much due to beingsprayed with fuel while a stoichiometric fuel-air mixture is present atthe spark plug.

German Unexamined Patent Application No. 38 20 509 describes aninjection nozzle with which diesel fuel is injected directly into acombustion chamber of a diesel engine. This injection nozzle has a valvebody having a valve opening surrounded by a valve seat to form a sprayopening. In addition, the spray nozzle has a valve needle which ispressed into its closed position, has a closing head and extends throughthe valve opening so that the closing head which works together with thevalve seat is in contact with the valve seat on the spray side when thevalve is closed. One or more edge grooves are provided on the downstreamend of a valve sleeve in the flow path upstream from the spray opening.

This injection nozzle is designed so that the injection sequence isdivided into several phases in which different flow paths in the nozzleare closed or opened so that different spray geometries are achieved inthe individual phases. In a first phase of valve opening, the valvesleeve completes an axial movement together with the valve needlearranged in its inside opening. Since the valve sleeve has severallongitudinal grooves running axially on its outside circumference, therecan be a preinjection in this way. With another stroke of the valveneedle, the longitudinal grooves are closed by the valve sleeve beinginserted into the valve body while a control bore is opened in the valvesleeve, so that fuel can enter the inside of the valve sleeve betweenthe latter and the valve needle. In this phase, string-like streams areproduced as part of the main injection through the edge grooves.Subsequently, the valve sleeve comes to rest against a stop that isstationary with respect to the housing, while the valve needle movesfurther in the opening direction. Consequently, an annular gap is formedbetween the lower edge of the valve sleeve and the closing head, so thatanother portion of the main fuel spray enters the combustion chamber inthe form of an umbrella stream under high pressure. With thisarrangement, strands of fuel are produced in chronological succession bymeans of an axially movable valve sleeve and its opening geometry andare then subsequently replaced by an umbrella pattern of the fuel.

In particular when the fuel channels are implemented in the form ofgrooves, it is possible to reduce manufacturing cost without sacrificingprecision in manufacturing. Using a metering disk having the fuelchannels, which is assigned to the inflow area of the valve opening,results in particular in an especially inexpensive embodiment of theinjection valve according to the present invention.

The safety of the injection valvel in operation can be improved throughthe stop means provided on the valve needle, because the valve needle isheld fast in the valve opening when there is a valve needle break, andthe injection valve is closed at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partially cutaway view of an exemplary embodiment of aninjection valve according to the present invention.

FIG. 2 shows a section through a valve unit of the injection valve.

FIG. 3 shows an enlarged diagram of the spray area of the valve unitaccording to FIG. 2.

FIG. 4 shows a section through the spray area of another valve unit.

FIG. 5 shows a section through the valve unit according to FIG. 4 with abroken valve needle.

FIG. 6 shows a section through another valve unit.

FIG. 7 shows a section through the spray area of the valve unitaccording to

FIG. 6 with a broken valve needle.

FIG. 8 shows a section through a device for attaching a securing tube ona valve needle.

FIG. 9 shows a section through the spray area of another valve unit.

FIG. 10 shows a section along the line X--X in FIG. 9.

FIG. 11 shows a section through the spray area of yet another valveunit.

FIG. 12 shows a section through a device for adjusting the flowresistance of fuel channels designed as grooves.

FIG. 13 shows a section through the spray area of yet another valveunit.

FIG. 14 shows a section through a device for grinding a guide sectionfor a valve needle in the valve body of the valve unit according to FIG.13.

FIG. 15 shows a section through a device for eroding fuel channelsdesigned as grooves in the valve body of the valve unit according toFIG. 13.

FIG. 16 shows a section through the spray area of yet another valveunit.

FIG. 17 shows a section along the line IV--IV in FIG. 16

FIG. 18 shows a section along the line V--V in FIG. 16.

FIG. 19 shows a section, similar to the section shown in FIG. 18,through another exemplary embodiment of the valve unit according to FIG.16.

FIG. 20 shows a section through another valve unit with a guide body fora valve needle.

FIG. 21 shows a section through a valve unit according to FIG. 20 withanother guide body.

DETAILED DESCRIPTION

As FIG. 1 shows, the injection valve according to the present inventionhas a valve housing 10 with an outlet tube 11 into which a valve unit 12is tightly inserted. As shown in FIG. 2, valve unit 12 includes. a valvebody 13 with a spring space 14 which is bordered by a bottom 15 on thespray side. A valve opening 17 surrounded by a valve seat 16 arranged onthe spray side is provided in bottom 15, with a valve needle 18 passingthrough the valve opening.

Valve needle 18, which has a closing head 19 working together with valveseat 16 and guided in valve opening 17 in the area of its closing head19, extends through spring space 14 and is permanently connected. at itsend facing away from closing head 19 to a guide bush 20 guided in springspace 14. Guide bush 20 has a recess 21 extending over its axial length,e.g., a flattened area designed as a ground planar section or one ormore grooves, so that fuel can flow into spring space 14.

A closing spring 22 which presses valve needle 18 into its closedposition is arranged on valve needle 18 between guide bush 20 and abearing ring 23 in contact with bottom 15. An actuating device (notshown) is provided for opening the injection valve; as indicated in FIG.1, this actuating device acts on valve needle 18 by way of an impactpart 24, moving the valve needle against the force of closing spring 22into its open position.

As shown in FIG. 3, valve opening 17 encloses a guide section 25 and aperipheral groove 26 provided between guide section 25 and valve seat 16surrounding valve opening 17. However, groove 26 can also be omitted, sothat guide section 25 of valve opening 17 extends as far as valve seat16.

Next to a sealing face 19' which is provided on closing head 19 of valveneedle 18 and works together with valve seat 16, a peripheral groove 27is provided on valve needle 18, bordering together with groove 26 anannular space 28 upstream from valve seat 16. If groove 26 of valveopening 17 is omitted, annular space 28 is bordered by groove 27 onvalve needle 18 and the part: of guide section 25 that is in the area ofgroove 27.

Fuel channels 29 designed as bore holes provided in bottom 15 of valvebody 13 are distributed around guide section 25 and, running obliquelyto valve needle 18, open into annular space 28. Individual fuel channels29 each have a defined cross section so that together they define anarrowest cross section in the flow path through the injection valve,determining the flow rate.

To inject fuel directly into a combustion chamber of an internalcombustion engine with such an injection valve, valve needle 18 is movedfrom its closed position into its open position. In doing so, an annularspray opening 30 is formed between valve seat 16 and sealing face 19'.Thus, when the injection valve is open, fuel flows out of spring space14 through fuel channels 29 into annular space 28 and further on tospray opening 30, through which the fuel is then sprayed.

A plurality of fuel streams or strands are produced by individual fuelchannels 29. The individual fuel streams or strands are deflected bysealing face 19' at valve needle 18, creating an essentiallyfrusto-conical fuel film or mist in the spray area of the injectionvalve, i.e., in the respective combustion chamber. The fuel streams areessentially preserved in flowing through annular space 28 and sprayopening 30, so that a stranded fuel distribution exists in the sprayedfuel film.

To influence the fuel distribution in the fuel film, the individual fuelchannels 29, the number of which may amount to about 5 to 20, may bespaced uniformly around the periphery or have different, preciselydefined peripheral spacings. In addition, it is possible for individualfuel channels 29 to be provided with a larger or smaller cross sectionso that the thickness of the individual fuel strands of the fuel filmsdiffers. Fuel channels 29 have diameters in the range of 0.05 mm to 0.2

The bore holes forming fuel channels 29 are produced by electricaldischarge machining or by laser boring. To set the common flowresistance of fuel channels 29 precisely at a predetermined level, fuelchannels 29 are machined by hydroerosion in particular. To do so, valveopening 17 is closed in the area of its guide section 25, and liquidabrasive is pumped under high pressure through fuel channels 29 untilthe desired flow resistance is achieved. In this machining, theinlet-side edges of fuel channels 29 become rounded, which reduces theflow resistance.

Injection valves in which valve needle 18 passes through valve opening17, with its closing head 19 in contact with valve seat 16 on the sprayside when the valve is closed, have the advantage that the individualelements for fuel metering and fuel distribution in the fuel film arecompletely separated from the unclean combustion chamber atmosphere whenthe valve is closed, so that no impurities which could impair theinjection function can be deposited on them.

In the event of breakage of valve needle 18, in order to prevent thebroken-off part of valve needle 18 from being forced through valveopening 17 into the combustion chamber under the pressure of fuel inspring space 14, it is advantageous to provide stop means on valveneedle 18 that work together with a counterstop provided for valveopening 17, so that movement of valve needle 18 is limited in thedirection of spraying without impairing the opening stroke of valveneedle 18 required for trouble-free operation of the injection valve.

As FIG. 4 shows, a securing ring 31, which is arranged in a peripheralgroove 32 on valve needle 18, may be provided as such a stop means. Toprevent securing ring 31 from interfering with normal operation of theinjection valve, bearing ring 23 has an axial flange 33 for closingspring 22, with bearing ring 23 being supported with said flange onbottom 15 of valve body 13.

If a valve needle break occurs, e.g., a crack 34 in valve needle 18close to its attachment to guide bush 20, then as shown in FIG. 5, thebroken-off part of valve needle 18 is pushed through valve opening 17 inthe direction of spraying until securing ring 31 comes to rest againstbottom 15 in the peripheral area of valve opening 17. Bottom 15 of valvebody 13 thus serves as a counterstop for securing ring 31.

The length of the displacement path of valve needle 18 allowed bysecuring ring 31 is greater than the axial distance of the upstream edgeof groove 27 from closing head 19. Thus valve needle 18 with its section18' which is located between groove 27 and securing ring 31 and isnormally guided in guide section 25 of valve opening 17 may extend intoa section of valve opening 17 directly next to valve seat 16 and thustightly seal valve opening 17. The section of valve opening 17 upstreamfrom valve seat 16 may be formed by a collar 35 between valve seat 16and groove 26 or, if there is no groove 26, by guide section 25. Collar35 has the same inside diameter as guide section 25.

In this way, in the event of a valve needle break, it is possible notonly to prevent fragments of valve needle 18 from entering thecombustion chamber and causing engine damage there but also to preventfuel from coming out of a damaged injection valve.

In another embodiment of the present invention, as shown in FIGS. 6 and7, a securing tube 36 is arranged on valve needle 18. Closing spring 22is supported on a shoulder 23' formed on bottom 15.

To fasten securing tube 36, a peripheral groove 32' is provided on valveneedle 18 close to guide bush 20, and securing tube 36 is pressed intothis groove with its end facing away from closing head 19.

The use of a securing tube 36 simplifies the assembly of the injectionvalve, because it can be mounted easily and accurately on valve needle18, independently of manufacturing tolerances.

For simple assembly of securing tube 36, a fastening device 37 is usedto advantage, having a stepped bore 38, as shown in FIG. 8, with alocating area 39 for valve body 13 and a section 40 next to that for theend of valve needle 18 having closing head 19. A central opening 41whose edge forms an adjusting stop for closing head 19 follows section40.

To attach securing tube 36 on valve needle 18 valve needle 18 is firstinserted into valve opening 17. Valve body 13 prepared in this way isthen inserted into locating area 39 of fastening device 37. Valve needle18 is then pushed out through valve opening 17 into section 40 ofstepped bore 38 until closing head 19 comes to rest on the edge ofopening 41. Then securing tube 36 is pushed onto valve needle 18 untilits one end abuts against bottom 15 in the area of valve opening 17. Theother end of securing tube 36 is then next to its edge facing away fromclosing head 19 by way of groove 32'.

Then the end of securing tube 36 facing away from closing head 19 can bepressed with the help of a tubular ram 42 into groove 32' so that it issecured on valve needle 18.

In another embodiment of the present invention illustrated in FIGS. 9and 10, grooves 43 are provided in the wall of valve opening 17 withguide webs 44 for valve needle 18 formed between them. Guide webs 44 endat a distance from valve seat 16, thus forming an annular space 45between the enlarged section of valve opening 17 and valve needle 18.Grooves 43 together with valve needle 18 then define fuel channels 29'opening into annular space 45. However, grooves 43 may also extend intothe area of valve seat 16.

To achieve a desired fuel distribution in the sprayed fuel film, thenumber of grooves 43 forming fuel channels 29', their free crosssection, their shape (round, rectangular, deep or wide) and theirperipheral distribution may be varied, as may also the respective sizesof fuel channels 29 formed by bore holes. It is also possible to designgrooves 43 to be helical in order to impart a swirl to a sprayed fuelfilm.

To ensure that in the event of a valve needle break in such an injectionvalve, not only will valve needle 18 be retained in valve opening 17 butalso valve opening 17 will be closed, securing ring 31 is provided witha chamfer 46 with which securing ring 31 abuts against a conical stopface 47 surrounding valve opening 17 in the event of a valve needlebreak, thereby sealing valve opening 17. Securing ring 31 is made of apolymer material to advantage, so that an especially reliable seal ofvalve opening 17 is achieved in the event of a valve needle break.

With the injection valve shown in FIG. 11, grooves 43 forming fuelchannels 29' end at a distance from valve seat 16. A collar 35' isprovided here between the spray end of grooves 43 and valve seat 16, itsdiameter corresponding to the guide diameter of valve opening 17 in thearea of guide webs 44. To form an annular space 28, a peripheral groove27 is provided on valve needle 18 directly next to closing head 19.

This makes it possible to achieve a valve seat diameter only slightlylarger than the diameter of valve opening 17, thus minimizing thesurface exposed to the fuel pressure in the injection valve and thecombustion chamber pressure. This has the advantage that lower forcesare sufficient to move valve needle 18. Thus the actuating device canalso be designed smaller accordingly. In particular, this makes itpossible to use smaller electromagnets for the actuating device, so theinjection valve is smaller and more compact on the whole.

When valve needle 18 is pushed into its open position shown in FIG. 11,this results in a flow path from spring space 14 through fuel channels29' to annular space 28 and further to annular spray opening 30, whichis delimited by valve seat 16 and sealing face 19' on closing head 19 ofvalve needle 18.

A special advantage of fuel channels 29' formed by grooves 43 is thatthey can be manufactured more quickly because two diametrically opposedgrooves 43 can be produced at the same time using a flat erodingelectrode.

This also has the advantage that a higher precision can be achieved inmanufacturing because flat eroding electrodes are stiffer than wireelectrodes used to produce bore holes.

The overall flow resistance of fuel channels 291 formed by grooves 43can be adjusted to particular advantage with an electrochemicalmachining method. As shown in FIG. 12, valve opening 17 is sealed forthis purpose by an insulating pin 48, which is made of ceramic, forexample, in the area between guide webs 44. Then a tubular electrode 49is placed on insulating pin 48 and brought into the inflow area ofgrooves 43. Then an electrolyte is pumped through spring space 14 andgrooves 43, as indicated by arrows 50. The flow resistance achieved ineach case can be measured easily during the electrochemical rounding ofthe inlet areas of grooves 43. To do so, the static flow rate ofelectrolyte can be determined at a constant pump pressure, for example.

In the case of valve unit 12 according to FIG. 13, valve opening 17 hasa conical section 17' on the inlet side, followed by a guide section 25'in the direction of valve seat 16. In the area of guide section 25',axial grooves are provided as fuel channels 29' with guide webs 44between them. Fuel channels 29' have inclined faces 70, running at aninclination at their outlet end and ending at a distance upstream fromvalve seat 16, thus forming a peripheral collar 35'. The angles betweeninclined faces 70 and the valve needle axis and between conical section17' and the valve needle axis are approximately the same.

Valve needle 18 has a peripheral groove 27 next to its closing head 19,developing into a cylindrical section 18' by way of conical face 27' onthe side facing away from closing head 19, thus forming a peripheraledge 71 on valve needle 18 lying in the area of inclined faces 70 offuel channels 29'. The angle between conical face 27' and the valveneedle axis is greater than the angles between inclined faces 70 and thevalve needle axis or between conical section 17' and the valve needleaxis.

When valve needle 18 is pushed into its open position during theoperation of the injection valve according to the present invention, thenarrowest cross section of the flow path through the injection valve isbetween edge 71 and inclined faces 70 of fuel channels 29'.

If a valve needle breaks, valve opening 17 is closed by cylindricalsection 18' of valve needle 18 which is pushed into the area of collar35', while securing ring 31 prevents valve needle 18 from being forcedcompletely out of valve body 13.

As shown in FIG. 14, valve body 13 is arranged on a locating mandrel 72of a fastening device 73 after forming conical section 17' of valveopening 17. Locating mandrel 72 has a conical tip 72' whose cone anglecorresponds to the cone angle of conical section 17'. As soon as valvebody 13 is arranged in the manner described here, guide section 25' andvalve seat 16 can be ground. FIG. 14 shows a grinding tool 74 forgrinding the guide section.

Due to the arrangement of valve body 13 with conical section 17' ofvalve opening 17 on the locating mandrel 72 of fastening device 73,radial eccentricities between conical section 17' and guide section 25'can be minimized.

To produce fuel channels 29', an eroding electrode 75 is first insertedtogether with its electrode guide 76 into spring space 14 of valve body13, as shown in FIG. 15.

Then eroding electrode 75 is adjusted to conical section 17' of valveopening 17 by reversing the polarity of the eroding current so that theinclination of side edges 77 of eroding electrode tip 78 corresponds tothe inclination of conical section 17'. Then fuel channels 29' areeroded.

The symmetry of inclined faces 70 of fuel channels 29' with respect toguide section 25' is very accurate due to the adjustment of erodingelectrode 75 to conical section 17'. This also yields a very accuratesymmetry of the sprayed streams of fuel.

If the fuel flow through the injection valve according to the presentinvention is to be increased at a given stroke of valve needle 18 andset at a predetermined value, this can be achieved easily by grindingconical face 27' delimiting groove 27.

With another injection valve according to the present invention as shownin FIGS. 16, 17 and 18, valve opening 17 has guide webs 51 distributedperipherally in bottom 15 of valve body 13, forming fuel flow areas 52between the webs, developing into an annular space 28 upstream fromvalve seat 16. A metering disk 53 having a central opening 54 throughwhich valve needle 18 passes and having a plurality of metering orifices55 which form fuel channels 29" sits on bottom 15 of valve body 13 andis held in contact with bottom 15 by closing spring 22.

As FIG. 18 shows, individual metering orifices 55 are combined intogroups and assigned to individual fuel flow areas 52 of valve opening17. In its contact area, metering disk 53 has a projection 56 whichextends toward bottom 15 of valve body 13 and may be formed by adepression or recess, for example, in metering disk 53 so that itengages or locks in a recess 57 in bottom 15. Due to the interaction ofrecess 57 with projection 56, the rotational position of metering disk53 relative to valve body 13 is fixed, so that the individual meteringorifices 55 are reliably assigned in the desired manner to fuel flowareas 52.

In another embodiment of metering disk 53' (FIG. 19), fuel channels 29"are formed by groove-like recesses 58 in the edge of central opening 54between which webs 59 are provided.

With this injection valve according to the present invention, valve unit12 can be manufactured especially inexpensively, because precisionmanufacturing of metering disk 53, 53' is possible and can be performedsimply. For example, metering disk 53, 53' may be punched or cut out byspark erosion machining or laser cutting. Furthermore, it is possible tomanufacture metering disk 53, 53' by electrochemical deposition orelectrochemical abrasion.

In another injection valve according to the present invention, as shownin FIG. 20, a guide body 60 is provided for valve needle 18, having acentraL bore 61 with a guide section 62 and an enlarged area 63 facingspring space 14. Bores forming fuel channels 29 extend from a shoulder64 between enlarged area 63 and guide section 62 to an end face 65 ofguide body 60 facing valve seat 16, and they open into annular space 28which is formed between guide body 60 and valve seat 16 in valve opening17.

Guide body 60 which is forced by closing spring 22 into valve opening 17preferably has a conical outside peripheral surface 66 with which it isin contact with a corresponding inside peripheral surface 67 of valveopening 17. Inside peripheral surface 67 of valve opening 17 ends at adistance upstream from valve seat 16, thus forming a collar 68 in thearea of which the diameter of valve opening 17 is larger than thediameter of valve needle 18.

With this embodiment, conical inside peripheral surface 67 of valveopening 17 can be ground together with valve seat 16 in one chucking, sothat inside peripheral surface 67 and valve seat 16 have very littleradial eccentricity. Similarly, central bore 61, the bores for fuelchannels 29 and conical outside peripheral surface 66 on guide body 60can be manufactured in one chucking with very little radialeccentricity. Thus, guide section 62 for valve needle 18 and valve seat16 can be aligned very accurately with one another when valve unit 12 isassembled.

When the injection valve described on the basis of FIG. 20 is opened tospray a fuel film, fuel flows from spring space 14 through enlarged area63 of central bore 61 and fuel channels 29 into annular space 28 andpast collar 68 to annular spray opening 30 which opens between valveseat 16 and sealing face 19' when closing head 19 is lifted from valveseat 16. The fuel streams or strands coming out of the fuel channels areessentially maintained.

As shown in FIG. 21, guide body 60 may be provided with grooves 69 or 43to form fuel channels 29' on its outside peripheral surface 66 (lefthalf of FIG. 21) or in guide section 62 of central bore 61 (right halfof FIG. 21).

The advantage of the design of grooves 69 forming fuel channels 29' inoutside peripheral surface 66 of guide body 60 is that fuel channels 29'can be manufactured especially easily and accurately.

The design of fuel channels 29' in guide section 62 yields an especiallyfavorable guidance of the fuel flow through the injection valve.

What is claimed is:
 1. A fuel injection valve, comprising:a valve seat;a valve body including a valve opening, the valve opening beingsurrounded by the valve seat to form a spray opening; a valve needleincluding a closing head which cooperates with the valve seat, the valveneedle being prestressed into a closed position, wherein when the valveneedle is in the closed position, the valve needle extends through thevalve opening to enable the closing head to contact the valve seat on aspray side of the valve needle; and a plurality of fuel channelsdistributed around a periphery of the valve body and situated in a flowpath upstream from the spray opening, the fuel channels having crosssections which define a flow-path cross-section through the injectionvalve, the flow-path cross-section determining a flow rate of a fuel,the fuel channels and the valve opening configured to maintain the fuelin streams or strands as the fuel emerges from the fuel channels untildownstream from the spray opening, the fuel channels being situateddirectly in the valve body upstream from the valve seat.
 2. Theinjection valve according to claim 1, wherein the injection valvedirectly injects the fuel into a combustion chamber of an internalcombustion engine.
 3. The injection valve according to claim 1, whereinthe fuel channels open into an annular space, the annular spacesurrounding the valve needle and being provided in the valve openingupstream from the spray opening.
 4. The injection valve according toclaim 1, wherein the fuel channels are bore holes.
 5. A fuel injectionvalve, comprising:a valve seat; a valve body including a valve opening,the valve opening being surrounded by the valve seat to form a sprayopening; a valve needle including a closing head which cooperates withthe valve seat, the valve needle being prestressed into a closedposition, wherein when the valve needle is in the closed position, thevalve needle extends through the valve opening to enable the closinghead to contact the valve seat on a spray side of the valve needle; aplurality of fuel channels distributed around a periphery of the valvebody and situated in a flow path upstream from the spray opening, thefuel channels having cross sections which define a flow-pathcross-section through the injection valve, the flow-path cross-sectiondetermining a flow rate of a fuel, the valve opening maintaining streamsor strands of the fuel, emerging from the fuel channels, untildownstream from the spray opening, the fuel channels being situateddirectly in the valve body upstream from the valve seat; and a guidesection including the fuel channels, the guide section guiding the valveneedle in an area of the closing head.
 6. A fuel injection valve,comprising:a valve seat; a valve body including a valve opening, thevalve opening being surrounded by the valve seat to form a sprayopening; a valve needle including a closing head which cooperates withthe valve seat, the valve needle being prestressed into a closedposition, wherein when the valve needle is in the closed position, thevalve needle extends through the valve opening to enable the closinghead to contact the valve seat on a spray side of the valve needle; anda plurality of fuel channels distributed around a periphery of the valvebody and situated in flow path upstream from the spray opening, the fuelchannels having cross sections which define a flow-path cross-sectionthrough the injection valve, the flow-path cross-section determining aflow rate of a fuel, the valve opening maintaining streams or strands ofthe fuel, emerging from the fuel channels, until downstream from thespray opening, the fuel channels being situated directly in the valvebody upstream from the valve seat; wherein the fuel channels are groovesin a wall of the valve opening which guides the valve needle.
 7. Theinjection valve according to claim 6, wherein the grooves include endinclined faces at an outlet portion, the end inclined faces and an edgeof the valve needle defining the flow-path cross-section.
 8. Theinjection valve according to claim 7, wherein the wall includes aconical section at an inlet end, the conical section forming a firstangle with an axis of the valve needle, the end inclined faces forming asecond angle with the axis, the first angle being equal to the secondangle.
 9. A fuel injection valve, comprising:a valve seat; a valve bodyincluding a valve opening, the valve opening being surrounded by thevalve seat to form a spray opening; a valve needle including a closinghead which cooperates with the valve seat, the valve needle beingprestressed into a closed position, wherein when the valve needle is inthe closed position, the valve needle extends through the valve openingto enable the closing head to contact the valve seat on a spray side ofthe valve needle; and a plurality of fuel channels distributed around aperiphery of the valve body and situated in a flow path upstream fromthe spray opening, the fuel channels having cross sections which definea flow-path cross-section through the infection valve, the flow-pathcross-section determining a flow rate of a fuel, the valve openingmaintaining streams or strands of the fuel, emerging from the fuelchannels, until downstream from the spray opening, the fuel channelsbeing situated directly in the valve body upstream from the valve seat;wherein the fuel channels open into an annular space, the annular spacesurrounding the valve needle and being provided in the valve openingupstream from the spray opening; and wherein a diameter of the valveopening in a first area corresponds to a guide diameter for the valveneedle, the first area positioned directly upstream from the valve seat,the valve needle including a peripheral groove delimiting the annularspace on an inside wall of the valve needle which is next to the closinghead.
 10. The injection valve according to claim 9, wherein the wallincludes a peripheral groove, the peripheral groove delimiting theannular space on an outside wall so that the valve opening includes acollar between the peripheral groove and the valve seat.
 11. A fuelinjection valve, comprising:a valve seat; a valve body including a valveopening, the valve opening being surrounded by the valve seat to form aspray opening; a valve needle including a closing head which cooperateswith the valve seat, the valve needle being prestressed into a closedposition, wherein when the valve needle is in the closed position, thevalve needle extends through the valve opening to enable the closinghead to contact the valve seat on a spray side of the valve needle; anda member including a plurality of fuel channels, the fuel channels beingsituated upstream from the valve seat separately from the valve body,the fuel channels being distributed around a periphery and situated in aflow path upstream from the spray opening, the fuel channels havingcross sections which define a flow-path cross-section through theinjection valve, the flow-path cross-section determining a flow rate ofa fuel, the valve opening maintaining streams or strands of the fuel,emerging from the plurality of fuel channels, until downstream from thespray opening, the member being permanently connected to the valve body.12. The injection valve according to claim 11, wherein the injectionvalve directly injects the fuel into a combustion chamber of an internalcombustion engine.
 13. The injection valve according to claim 11,wherein the fuel channels open into an annular space which surrounds thevalve needle, the annular space being provided in the valve openingupstream from the spray opening.
 14. The injection valve according toclaim 11, wherein the fuel channels are bore holes.
 15. The injectionvalve according to claim 11, further comprising:a metering diskincluding the fuel channels and a central opening for the valve needle,the metering disk being used for an inlet area of the valve opening. 16.The injection valve according to claim 15, wherein metering orifices ofthe metering disk form the fuel channels.
 17. The Injection valveaccording to claim 15, wherein recesses in an edge of the centralopening form the fuel channels.
 18. The injection valve according toclaim 15, wherein fuel flow areas extend axially in the valve openingand are situated between guide webs for the valve needle, a part of thefuel channels being assigned to the fuel flow areas.
 19. A fuelinjection valve, comprising:a valve seat; a valve body including a valveopening, the valve opening being surrounded by the valve seat to form aspray opening; a valve needle including a closing head which cooperateswith the valve seat, the valve needle being prestressed into a closedposition, wherein when the valve needle is in the closed position, thevalve needle extends through the valve opening to enable the closinghead to contact the valve seat on a spray side of the valve needle; anda member including a plurality of fuel channels, the fuel channels beingsituated upstream from the valve seat separately from the valve body,the fuel channels being distributed around a periphery and situated in aflow path upstream from the spray opening, the fuel channels havingcross sections which define a flow-path cross-section through theinjection valve, the flow-path cross-section determining a flow rate ofa fuel, the valve opening maintaining streams or strands of the fuel,emerging from the plurality of fuel channels, until downstream from thespray opening, the member being permanently connected to the valve body;wherein the member further includes a conical guide body, the conicalguide body being inserted, as a guide part for the valve needle, intothe valve opening, the valve opening having a conical section.
 20. Theinjection valve according to claim 19, wherein the fuel channels aregrooves in a conical outside peripheral surface of the conical guidebody.
 21. A fuel injection valve comprising:a valve seat; a valve bodyincluding a valve opening, the valve opening being surrounded by thevalve seat to form a spray opening; a valve needle including a closinghead which cooperates with the valve seat, the valve needle beingprestressed into a closed position, wherein when the valve needle is inthe closed position, the valve needle extends through the valve openingto enable the closing head to contact the valve seat on a spray side ofthe valve needle; and a plurality of fuel channels distributed around aperiphery of the valve body and situated in a flow path upstream fromthe spray opening, the fuel channels having cross sections which definea flow-path cross-section through the injection valve, the flow-pathcross-section determining a flow rate of a fuel, the valve openingmaintaining streams or strands of the fuel, emerging from the fuelchannels, until downstream from the spray opening, the fuel channelsbeing situated directly in the valve body upstream from the valve seat;a stop arrangement positioned on the valve needle; and a counterstopcooperating with the stop arrangement, the counterstop being situated atthe valve opening to limit movement of the valve needle in a spraydirection, wherein, when the valve needle is in the closed positioned, aparticular distance between the stop arrangement and the counterstop isgreater than an opening stroke of the valve needle.
 22. The injectionvalve according to claim 21, wherein the stop arrangement is retained ina groove of the valve needle.
 23. The injection valve according to claim21, further comprising:a securing ring including the stop arrangement.24. The injection valve according to claim 23, wherein the securing ringis composed of a polymer material.
 25. The injection valve according toclaim 21, further comprising:a securing tube including the stoparrangement.